It’s very easy to see that the growth of meat and milk production is driven by the growth in demand from the table of per capita consumption of meat and milk. The increasing of consumption demand has encouraged the rapid development of cattle farming industry. As cattle farming scale enlarges day by day, the quantity of cow dung has become larger and larger. According to the report, the manure produced by one cattle per day equates about 5%-6% of its weight, in other words, a cattle with 450kg weight can excrete about 25kg manure per day averagely, then there is more than 9000kg for one year. In general, all types of cattle produce large amounts of manure: milk cows(62 kg/day), bulls (42 kg/day), beef cows (37 kg/day), steers (26 kg/day), heifers (24 kg/day) and calves (12 kg/day), so the quantity of cow dung from a cattle farm with certain scale is very huge.

For instance, agriculture is still one of the main sources of the national income in Thailand, contributing to 11% of GDP, thereinto, livestock plays an important role in agricultural sector, accounting for 22% of agricultural GDP (Office of Agricultural Economics, 2014), while cattle raising has been identified as 1 of 14 main products in Thai agriculture, which brings enormous quantity of cow dung. In Vietnam, cattle farming is an important industry in the livestock sub-sector, being the third largest industry after pigs and

poultry, also producing lots of manure. By 2020 the Malaysia government has targeted to raise the self-sufficiency level of beef to 32.7% (MAO, 2015), which translates in the slaughter of more than 450,000 head of cattle each year. All these data signify a great deal of cow manure output.

Without proper disposal, cow dung would cause a series of issues to environment and even become a direct threat to human and livestock health. It generates lots of greenhouse gas – methane, not only seriously restricting the sustainable development of cattle farming industry, but also having adverse impact on climate change. The untreated manure would heavily pollute surface water, underground water, surrounding air and soil, bringing big hidden trouble and pressure for environment protection. Therefore, proper disposal for cow dung is extremely urgent.

Currently, the most common and valuable processing method is to turn cow dung/manure into sellable organic fertilizer. Cow dung is a derived product from wastes produced by cattle, providing high levels of organic materials and rich in nutrients, including about nitrogen, phosphorous and potassium as well as many other essential nutrients. According to the data, daily cow dung contain 12.9% DM and excreting a total of 0.15kg N, 0.04kg P and 0.08kg K. Moreover, cow manure also contains high levels of ammonia that can almost kill the growth of the pathogens. Once raw cow dung composted by professional compost turner, it can provide lots of benefits to the garden and organic farm, which makes cow manure very popular and useful raw material of organic fertilizer production.

Cow Dung Waste Management – How to Process it into Quality Organic/Compost Fertilizer?

As one of the most important source to prepare effective bio/organic fertilizer, the processing method of cow dung organic fertilizer is first to collect the cattle residue. Heavy cow manure should be mixed with organic substances like vegetable waste, garden debris, dead leaves, sawdust, wood ash, hay and straw etc. The mixed cow dung is then subjected to better composting and fermentation via compost turner machine. After fully composting, cow dung would be transferred into crusher for materials grinding, in order to make sure smooth granulating process. Remember to choose a suitable organic fertilizer granulator according to the scale of cow manure composting and production. Usually, for easy packaging and storage, a rotary dryer would be used to evenly dry the granules and ultimately create a uniform and quality final product. Finally, we also provide an automated packaging machine so as to fulfill high-efficiency, automatic and convenient packaging and bagging solution for finished organic fertilizers. Here, we will discuss the two major procedures of cow dung disposal – aerobic composting process and granulation process in detail.

Composting of Cow ManureCow manure should not be used before composting because fresh cow dung with dangerous bacteria might hurt crop roots, and it also contains grass or weed seeds that would lead to havoc for plant growing. Hence, cow dung needs to rot — turning into a more flexible compost in the process that can destroy the harmful bacteria and kill many microbes and weed seeds. There are some useful tips for cow dung composting:

◇ Select a flat and open location where you can pile up all collected manure. And leave enough space for compost turner machine to turn piles breezily.
◇ If the moisture of fresh cow dung is up to 60% – 80%, it is necessary to make dewatering, which might need Whirlston provides solid-liquid dewatering machine – specially designed for manure separation as well as for dewatering, assisting in lowering the water content in fresh cow manure.

Watch the working video of manure dewatering machine:

◇ There are three main composting techniques for cow dung, including windrow composting(piling cow dung in long rows/windrows), groove-type composting, cabin composting. Please consider the investment cost, composting scale, composting quality and efficiency, land area, operation ability and weather effect when choosing composting method. For instance, with piling cow manure in long rows (like 50-150 meters, about 2 meters width and 1m height), windrow compost turnerwould be needed for continuous turning operation because windrow composting method is suitable for process large volumes of cow manure.
◇ The composting and fermentation extent can be estimated according to compost color, volume, leach liquor, CN ratio and humification coefficient. To be specific, mature compost has brown or dark brown color due to the obvious increasing of ammonium nitrogen content. Its volume would shrink by 1/3~1/2 than original piles after fully fermentation. Besides, adding clean water into mature compost (the ratio of water and compost should be 1:5-10), then mixing, the color of leach liquor would assume faint yellow after 5 minutes waiting. And the CN ratio of mature compost is about 20-30:1 while its humification coefficient is around 30%.

Granulation of Cow DungAfter thorough composting, cow manure has become harmless, but because of the low total nutrient and drawback of difficult and costly to transport, the compost can only be used as a part of base fertilizer and cannot flow into the market for sale as commercialized products, all of which limit the application ranges and using effect. And cow dung cannot provide sufficient nutrients to promote maximum growth and optimum forage quality. Therefore, it’s essential to turn cow dung compost into granulated organic fertilizer through the following granulation process, creating a potential new source of revenue and making this process a win-win proposition.

Cow dung granulation is a method of agglomerating manure into a dry product known as granules, pellets, or agglomerates, which requires that cow dung should contain about 45%-55% water content so as to produce granular manure fertilizer. Here, Whirlston recommends disc pan granulator for improving the efficiency and quality of the final product. This machine provides control through variations in speed, incline and constant rotating and spraying mechanism, producing more dense and rounded granules.

Benefits of Cow Manure Composting Organic Fertilizer

※ With satisfactory NPK content, cow dung organic fertilizer after composting and granulation can eliminate harmful ammonia gas and pathogens, add large amount of organic matter to the soil and supply plant nutrients.
※ It is an important input for maintaining and enhancing soil fertility, which can grow up healthy vigorous plant, and improve agricultural productivity and crop output, which is a need of a developing nation, such as Vietnam, Thailand and Philippines, etc. So the application of cow dung organic fertilizer in proper and sustainable way can enhance not only productivity of crops yield but also reduce disease incidence caused by a wide range of plant pathogens including bacteria, fungi, and nematode species.
※ What’s more, making cow dung into organic fertilizer is conducive to environment protection by greatly reducing foul smell, air pollution and mosquitoes and flies harm caused by cow manure.